Dr. Bauldry is using flexible fiberoptic bronchoscopy with bronchoalveolar lavage on normal subjects for the express purpose of establishing a normal range or standard for total cell count, cells recovered per ml of returned (aspirated) volume, cellular differential including alveolar macrophages, lymphocytes, PMN's, eosinophils, monocytes, mast cells, and bronchial epithelial cells. In addition, assays for identifying sub-populations of cells will be developed. Normal ranges for select biochemical parameters will be assessed.